Study of the distribution of phenotypic characteristics of sunflower seeds in a head of different genotypes

Nowadays, sunflower breeding needs new approaches and methods. Using computer-aided image analysis techniques combined with other data on the phenotyping subject creates a sound basis for selection. Selection work on the size and weight of sunflower seeds causes many complications related to the variety of seeds, even in one head. To solve this problem, field experiments, mathematical modelling, and computer processing of photographs were involved. As a result of combining the results of actual measurement and evaluation of photographic images, a method of measurement and determination of patterns of distribution of phenotypic characteristics of sunflower seeds in a head was developed. The methodology includes a developed mathematical model of the location of sunflower seeds in the head and a methodology for determining the geometric dimensions of the seeds from the image. The distribution patterns of geometric (length L, width W, thickness T) and mass (seed mass Ms, seed kernel mass Mk) parameters of seeds in the head were studied. The variability of the seed phenotype in the head was established depending on its location based on the material of four lines and the sunflower variety. A complex index of phenotypic characteristics of sunflower seeds I is introduced, defined as the product of the ranks of individual phenotypic parameters of seeds (L, W, T, Ms, Mk). A general pattern was determined, like three tiers with different phenotypic characteristics in each head. The possibilities of visualising the phenotype of seeds by their location in the head have been revealed.